Nicholas Key Nicholas Key Principal Software Engineer in Test at Okta Published Dec 16, 2016
I thought of sharing this cheat sheet that is easy enough to understand and might be useful for anyone that codes in Python or would like to know more about the various ways to slice a list in Python. My personal experience with slicing a list in Python is summarized in this image so that you may find it handy, and share it around, if you want to. However, do keep in mind that while some notations to slice a list might seem advance, they may not be as readable as compared to a
few lines of codes. So, make your own judgement wisely :) Collection of List slicing patterns for Python Notations:list[:] >> All
list[Low:] >> Low to End
list[:High] >> Begining to High
list[Low:High] >> Low to High
list[::Step] >> Start to End with Step
list[Low::Step] >> Low to End with Step
list[:High:Step] >> Start to High with Step
list[Low:High:Step] >> Low to High with Step
Examplelist= ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I']
Simple list[3] >> 'D'
list[-3] >> 'G'
list[:] >> ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I']
list[3:] >> ['D', 'E', 'F', 'G', 'H', 'I']
list[:3] >> ['A', 'B', 'C']
list[-3:] >> ['G', 'H', 'I']
list[:-3] >> ['A', 'B', 'C', 'D', 'E', 'F']
Double list[-12:1] >> ['A']
list[-12:3] >> ['A', 'B', 'C']
list[-12:-3] >> ['A', 'B', 'C', 'D', 'E', 'F']
list[1:-8] >> []
list[1:-11] >> []
list[1:-6] >> ['B', 'C']
list[2:6] >> ['C', 'D', 'E', 'F']
Double with
step list[2:7:4] >> ['C', 'G']
list[2:7:5] >> ['C']
list[2:7:2] >> ['C', 'E', 'G']
list[1:8:2] >> ['B', 'D', 'F', 'H']
list[-7:8:2] >> ['C', 'E', 'G']
More variations list[-1::] >> ['I']
list[-3::] >> ['G', 'H', 'I']
list[3::] >> ['D', 'E', 'F', 'G', 'H', 'I']
list[::-1] >> ['I', 'H', 'G', 'F', 'E', 'D', 'C', 'B', 'A']
list[::-4] >> ['I', 'E', 'A']
list[::4] >> ['A', 'E', 'I']
list[::-2] >> ['I', 'G', 'E', 'C', 'A']
list[::2] >> ['A', 'C', 'E', 'G', 'I']
Even more variations list[-7::2] >> ['C', 'E', 'G', 'I']
list[-7::3] >> ['C', 'F', 'I']
list[1::-1] >> ['B', 'A']
list[1::-2] >> ['B']
list[1::-7] >> ['B']
list[6::-3] >> ['G', 'D', 'A']
If you have any more patterns, ideas or suggestions, please share. You can fork/start this at https://github.com/ostwalprasad/PythonListSlicingCheatsheet |
